Disclosed are biocontrol agents for the control of insects (e.g., moths and mosquitoes such as Aedes aegypti), in particular Chromobacterium vaccinii strains capable of killing insects such as mosquitoes and moths. More specifically, disclosed are Chromobacterium vaccinii strains MWU205 (NRRL B-50840), MWU300 (NRRL B-50841) and MWU328 (NRRL B-50842). Also disclosed are biocontrol strategies whereby insects (e.g. mosquitoes, moths) are exposed to the Chromobacterium vaccinii strains MWU205, MWU300 or MWU328 as a method for killing insects, including insect larvae in more than one taxonomic order.
After the discovery of a new species of Chromobacterium, C. subtsugae, that killed insects (Martin, P. A. W., et al., International Journal of Systematic and Evolutionary Microbiology, 57: 993-999 (2007); U.S. Pat. No. 7,244,607), we tested other chromobacteria for insecticidal activity. In the case of C. violaceum, the type strain of this species (ATCC 12472T) was not toxic to several species of insects (e.g. Colorado potato beetle, diamondback moth, southern corn rootworm) whereas C. subtsugae was toxic. C. subtsugae, although it kills a variety of insects, was not effective against mosquito larvae at similar concentrations and short time frames (16 h) compared to the ‘gold standard’ bacterial strain Bacillus thuringiensis var. israelensis (Bti; IBL 10003). Bti is an effective control agent of mosquitoes and black flies (Goldberg, L. J., and J. Margalit, Journal of the American Mosquito Control Association, 37: 355-358 (1977)) over the 30 years it has been in use. More recently resistance to the Cry toxin of Bti has been described in both Lepidoptera (moths) and Aedes mosquitoes (Cancino-Rodenzo et al., Insect Biochem. Mol. Biol., 40: 58-63 (2010)). Another sporeforming bacterium (Lysinobacillus sphaericus) also negatively affects mosquito larvae (Davidson, E. W., Mosq. News, 44: 147 (1984)) but no non-sporeforming bacteria are known to do so. Additionally, reliance on a single mode type of bacteria (i.e., Bti) is not the best long-term strategy for insect control because of the emergence of Bt resistance, and particularly in cases like mosquito control where it may not be possible or desirable to incorporate insect ‘refuges’ (Tabashnik, B. E., et al., J. Econ. Entomol., 96(4): 1031-8 (2003)).
With 219 million annual cases of malaria, over 100 million annual cases of dengue hemorrhagic fever, 200,000 cases of yellow fever, and millions of cases of other mosquito-borne infectious and parasitic diseases such as West Nile and chikungunya, coupled with insect resistance to chemical insecticides, there is a critical and global need for new biocontrol agents for insects such as mosquitoes.